1. Field of the Invention
The present invention relates to a monitoring system adapted to acquire operational information associated with an image forming apparatus disposed at a user site.
2. Description of the Related Art
In a conventional monitoring system, such as that disclosed, for example, in Japanese Patent Laid-Open No. 04-318746, a monitoring apparatus installed at each user site acquires information indicating the operational status of an image forming apparatus such as a printer, a copying machine, or a multifunction apparatus installed at the user site and billing information, and transmits the acquired information to a host apparatus installed at a monitoring center such as a service center (or a sales company). In accordance with the received information, the host apparatus at the monitoring center manages all apparatus installed at respective user sites. More specifically, for example, information such as count data indicating the number of printed sheets, or information indicating an occurrence of a failure such as a paper jam, is transmitted to the monitoring apparatus via a communication line, and the monitoring system transfers the information to the service center that manages the image forming apparatus.
However, this conventional monitoring system has a problem with security of information, and thus there is a need for a technique that ensures high security of information in maintaining image forming apparatus.
A public communication line such as the Internet is used for connections between a plurality of monitoring apparatus installed at user sites and the monitoring center host computer system that manages the monitoring apparatus. In the case of transmission of data via such a communication line, data may be encrypted to achieve security of the data. However, when data is encrypted using a public key cryptosystem, only the monitoring center host computer system is allowed to decrypt the data. This causes the problem that when a checker at a user site wants to check the content of data transmitted from a monitoring apparatus at the user site to the monitoring center host computer system, the checker cannot read the data because it is encrypted.
Another problem is that if a decryption key (common key) used to decrypt data transmitted to the monitoring center host computer system is leaked to an unauthorized person, the unauthorized person can decrypt and read the data. This causes a problem with low security.